Answer:
a) the number-average molecular weight is 32,400 g/mol
b) the weight-average molecular weight is 36,320 g/mol
c) the degree of polymerization is 770
Explanation:
Given the data in the question;
Molecular Mean Number Weight Number Weight
weight average average
(g/mol) Mi(g/mol) xi wi xiMi wiMi
8,000-16,000 12,000 0.07 0.03 840 360
16,000-24,000 20,000 0.15 0.09 3000 1800
24,000-32,000 28,000 0.26 0.21 7280 5880
32,000-40,000 36,000 0.27 0.27 9720 9720
40,000-48,000 44,000 0.18 0.28 7920 12320
48,000-56,000 52,000 0.07 0.12 3640 6240
∑ Mn=32,400 Mw=36,320
so;
a) the number-average molecular weight
Mn = ∑Mixi
so from the table above; summation of Row Mixi
Mn = ∑Mixi = 32,400
Therefore, the number-average molecular weight is 32,400 g/mol
b) the weight-average molecular weight
Mw = ∑Miwi
so from the table above; summation of Row Miwi
Mw = ∑Miwi = 36,320
Therefore, the weight-average molecular weight is 36,320 g/mol
c) the degree of polymerization
the degree of polymerization of polypropylene can be determined using number-average molecular and repeat unit molecular weight.
now, for polypropylene { CH₂ = CH - CH₃ }
the repeat unit consist of 3 carbon atoms and 6 hydrogen atoms
given that;
Atomic weight of Carbon mC = 12.01 g/mol and
Atomic weight of Hydrogen mH = 1.008 g/mol
now we find the repeat unit molecular weight of polypropylene
m = nCmC + nHmH
where n is the number of repeat of atoms
so we substitute
m = ( 3 × 12.01) + ( 6 × 1.008)
m = 36.03 + 6.048
m = 42.078 g/mol
now we calculate the degree of polymerization;
DP = Mn / m
so we substitute
DP = 32,400 / 42.078
DP = 769.9985 ≈ 770
Therefore, the degree of polymerization is 770
What can she find out from her experiment?
A. If soaked bean seeds sprout faster
B. If dry bean seeds require more water
C. If dry bean seeds produce taller plants
D. If soaked bean seeds require more sunlight
Answer:
B. If dry bean seeds require more water
I hope it is helpful..
most ponds contain both slat water and fresh water. true or false
Answer:
False
Explanation:
Freshwater habitats include ponds, lakes, rivers, and streams, while marine habitats include the ocean and salty seas.
Based on the following equation, how many moles of hydrochloric acid (HCl)are needed to react with 0.44 moles of potassium
permanganate (KMnO4)?
2KMnO4 + 8HCI - 3Cl2 + 2MnO2 + 4H2O + 2KCI
Answer:
1.76 moles of HCl.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2KMnO₄ + 8HCl —> 3Cl₂ + 2MnO₂ + 4H₂O + 2KCl
From the balanced equation above,
2 moles of KMnO₄ reacted with 8 moles of HCl.
Finally, we shall determine the number of mole of HCl needed to react with 0.44 moles of KMnO₄. This can be obtained as follow:
From the balanced equation above,
2 moles of KMnO₄ reacted with 8 moles of HCl.
Therefore, 0.44 moles of KMnO₄ will react with = (0.44 × 8)/2 = 1.76 moles of HCl.
Thus, 1.76 moles of HCl is needed for the reaction.
who is the father of phycis
Galileo Galilei
hope it helps you
Answer:
Galileo Galilei is the father of Physics
I hope it helps ❤❤
1. The equation for the reaction between zinc and aqueous copper(II) sulfate is shown.
Zn + Cuso, → ZnSO, + Cu
Which statement is correct?
a. The oxidation state of the oxidising agent has changed from 0 to +2.
b. The oxidation state of the reducing agent has changed from 0 to +2.
c. The oxidation state of the reducing agent has changed from +2 to 0
d. This is not a redox reaction. The solution changes from colourless to blue.
Answer:
The oxidation state of the reducing agent has changed from 0 to +2.
Explanation:
reducing agent is anything that loses electron or gains oxygen
in this case, zinc
What a main difference between Earth and Jupiter?
A. Earth is an inner planet with a solid rock surface composition, while Jupiter is an outer planet with a gas surface composition.
B. Earth is an inner planet with a relatively long distance from the sun, while Jupiter is an outer planet with a relatively short distance from the sun.
C. Earth is an outer planet with a gas surface composition, while Jupiter is an inner planet with a solid rock surface composition.
D. Earth is an outer planet with a relatively short distance from the sun, while Jupiter is an inner planet with a long distance from the sun.
Answer: A. Earth is an inner planet with a solid rock surface composition, while Jupiter is an outer planet with a gas surface composition.
Answer: What a main difference between Earth and Jupiter?
Earth is an inner planet with a solid rock surface composition, while Jupiter is an outer planet with a gas surface composition.
Earth is an inner planet with a relatively long distance from the sun, while Jupiter is an outer planet with a relatively short distance from the sun.
Earth is an outer planet with a gas surface composition, while Jupiter is an inner planet with a solid rock surface composition.
Earth is an outer planet with a relatively short distance from the sun, while Jupiter is an inner planet with a long distance from the sun.
Explanation:
Given the following:
Measurement Reaction 1 (Mg + HCl)
Mass of HCl (g) 100.50
Mass of solid (g) 0.20
Total mass of reactants, m (g) (add the masses above) 100.70
Initial Temperature (°C) 22.5
Temperature furthest from initial temperature(°C) 31.3
∆T(°C) Subtract the two temperatures above) 8.8
Given Reaction 1: Mg(s) + 2HCl(aq) ⟶ MgCl2(aq) + H2(g)
What is the ∆H (kJ/mol)?
Answer:
∆H = - 450 kJ/mol
Explanation:
You can calculate the change in enthalpy provided we have the heat of solution (q). That would be the only approach to this problem. But this approach is only possible if we have a specific set-up; we would have to use a calorimeter. So then the reactants are taken as the system, and water as the surroundings. When calculating q, the heat of the solution, we take 4.18. Remember that heat is flowing from the reaction mixture, to the water, from the system to surroundings, so it's exothermic and ∆H = negative:
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
Answer:
the change in energy of the gas mixture during the reaction is 227Kj
Explanation:
THIS IS THE COMPLETE QUESTION BELOW
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
From thermodynamics
ΔE= q + w
Where w= workdone on the system or by the system
q= heat added or remove
ΔE= change in the internal energy
q=+ 319kJ ( absorbed heat is + ve
w= -92kJ
If we substitute the given values,
ΔE= 319 + (-92)= 227 Kj
With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.
How many TOTAL CELLS are created after a single cell goes through THREE COMPLETE CYCLES of mitosis?
Answer:
4 cells are made after 3 rounds of mitosis
Explanation:
According to the ideal gas law, what happens to the volume of a gas when the pressure doubles (all else held constant)?
Convert 10.0 g of iron (II) sulfate to moles.
please explain how to do this! I don't understand
Explanation:
number of moles =mass /relative molecular mass
n=10g/mr(FeSO4)
N=10/(56+32+16×4)
N=10/152
N=0,066 moles
Help! I’ll give brainliest if u get it right!
Answer:
That is the Atomic mass
Explanation:
The element symbol is S, Element name is sulfur, and
Atomic number is 16
What mass of Iron (III) acetate will be produced when 1.50 grams of iron reacts in acetic acid?
Fe + H(C2H3O2) ® Fe(C2H3O2)3 + H2
Answer:
Fe + H(C2H3O2) ........
A student connects a battery to a wire and wraps the wire around an iron nail to produce an electromagnet. Which action
should the student take to increase the number of paper clips the electromagnet can pick up?
He should replace the iron nail with a plastic spoon.
He should add another battery.
He should decrease the current through the wire
He should reduce the number of turns
Answer:
He should add another battery.
Explanation:
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a core of magnetic material usually an iron core. When an electric current-producing battery is connected to the wire, an electric current will begin to flow and the iron core will become magnetized. When the battery is disconnected, the iron core will lose its magnetism.
Electromagnets works based on the electromagnetic field which is a field force due to the interaction of the electric and magnetic fields. the force on the wire is proportional to the size of the current, the length and thickness of the iron core, as well as the number of turns of wire around the iron core.
Therefore, from the number of possible action given that the student can take in order to increase the magnetism of his electromagnet, adding another battery, thereby increasing the current will be the best way to increase the number of paper clips tat his electromagnet can pick up.
Answer:
they are correct he should add another battery trust me
help po
what is ecosystem?
what is a rainforest?
what are the major parts of rainforest?
what are coral reefs?
what are the different types of coral reefs?
Answer:
ecosystem:a biological community of interacting organisms and their physical environment.
rainforest: a luxuriant, dense forest rich in biodiversity, found typically in tropical areas with consistently heavy rainfall.
major part of rain forest:Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor. Each layer has unique characteristics based on differing levels of water, sunlight, and air circulation.
coral reefs :a ridge of rock in the sea formed by the growth and deposit of coral.
type of coral reefs:fringing reefs, barrier reefs, atolls, and patch reefs
Explanation:
mark me as brainliest and follow me
Explanation:
1)An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows.2)Rainforests are forests characterized by high and continuous rainfall, with annual rainfall in the case of tropical rainforests between 2.5 and 4.5 metres and definitions varying by region for temperate rainforests3) Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor. Each layer has unique characteristics based on differing levels of water, sunlight, and air circulation.4) A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. ... They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas.5)The three main types of coral reefs are fringing, barrier, and atollHope it help ful100. The compound Na FCN).NOJ is known as
Answer:
Na=sodium FCN=Cyanogon Flouride. NOJ =DEOXYNOJIRIMYCIN/MORANOLINE
Jen is conducting an experiment involving a device known as a pith-ball electroscope, shown below.
silk thread
-plastic ball
insulated
stand
The plastic ball of the electroscope hangs in midair and is uncharged. Charges cannot move along the silk thread that holds the
ball in the air
Jen completes the following steps in her experiment
1. She collects three identical, uncharged rubber tubes
2. She holds a magnet to the first tube for 5 minutes.
3. She submerges the second tube in a tank of water for 5 minutes
4. She rubs the third tube with animal fur for 5 minutes.
Jen's teacher tells her that she can use the pith-ball electroscope to see if any of the rubber tubes are surrounded by an electric
field. What should Jen do to test for an electric field surrounding each tube?
O A. bring the magnet close to the plastic ball and note any motion of the ball toward the magnet
OB.
connect the three tubes to each other and see if they attract the plastic ball
C. hold the magnet in direct contact with the tube that was submerged in water
OD. bring each tube close to the plastic ball and note any movement of the ball
12 of 30 Answered
Session Timer: 35:32
Session Score: 33 (4/12)
Answer:
A) bring the magnet close to the plastic ball and note any motion of the ball toward the magnet
Explanation:
DECREASES the erosion of agricultural lands.
A)
Planting cover crops
B)
Allowing the land lie fallow
c)
Alternating planting and grazing
D)
Plowing the land several months before planting
Answer:
I would say A. to be honest
The atoms in a copper bar are held together by metallic bonding. What would happen you ran over a copper bar with a car? It would . A. shatter B. become a covalent compound C. become an ionic compound D. be bent or flattened into a different shape
The answer is D.
Hope this helps!
Answer:
i would say D mostly because I don't know what the other ones mean
Explanation:
(just looked them up and I still think its D)
The electrical current in a circuit is measured in which of the following units
Answer:
joules
Explanation:
i think
Explanation:
The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit Electric current is measured using a device called an ammeter.
How many electrons were transferred if the total charge of a process is 929.5 C?
Answer:
5746.25×e.
Explanation:
The electron is known as the subatomic particle which revolves around the nucleus by possessing the negative charge.
when the atoms are involved in the reaction or process these electrons are transferred are gained by the atoms.
Coulomb is the term used to express the charge of the electrons.
In normal 1 coulomb of charge possess 6.25× electrons.
So here the total charge of the process is 919.4c in order to find number of electrons transferred is found by the product of 919.4 × 6.25× = 5746.25 × .
Thus the number of electrons transferred is obtained. the transferred electrons are 5746.25 ×.
Following a chemical reaction that produced 5.06 grams of magnesium chloride, the lab report was prepared to
document the results. The expected result was estimated to be 8.85 grams. What are the percent yield and percent
error that are to be included in the lab report?
Percent Yield
Percent Error
Answer:
1. Percentage yield = 57.2%
2. Percentage error = 74.9%
Explanation:
From the question given above, the following data were obtained:
Actual yield = 5.06 g
Experimental yield = 8.85 g
Percentage yield =?
Percentage error =?
1. Determination of the percentage yield.
Actual yield = 5.06 g
Experimental yield = 8.85 g
Percentage yield =?
Percentage yield = Actual yield /Experimental yield × 100
Percentage yield = 5.06 / 8.85 × 100
Percentage yield = 57.2%
2. Determination of the Percentage error.
Actual yield = 5.06 g
Experimental yield = 8.85 g
Percentage error =?
Percentage error = |Experimental – Actual| / Actual yield × 100
Percentage error = |8.85 – 5.06| / 5.06 × 100
Percentage error = 3.79 / 5.06 × 100
Percentage error = 74.9%
What is it called when instead of getting rid of a product you find another
use for the product?
Answer:
Recycling.
Explanation:
When instead of getting rid of a product you find another use for the product, it is called recycling.
Recycling can be defined as a process which typically involves gathering, processing and transformation of materials or products that would otherwise be gotten rid of as waste materials or trash into new products that could be used for another purpose.
Basically, the recycling process involves turning a trash or unwanted product into a treasure (new product) that is capable of serving another purpose.
For example, the crown cork of a bottle could be gathered and processed into art forms that can be used for decorations.
(04.02 LC)
During photosynthesis, water and carbon dioxide become glucose and oxygen.
True
False
Answer:
true............,....
Answer:False
Explanation:
This statement is false. Correct statement: Photosynthesis produces glucose and oxygen. ... In this process, plants produce glucose and oxygen from carbon dioxide and water in the presence of sunlight. Photosynthesis converts light energy into chemical energy.
Discuss why it is not necessary to know exactly how much salt was added to the water in making the salt solution to just float the egg?
Answer and Explanation:
It is not necessary to know the amount of salt in the aqua, because we know that the presence of salt in the water will increase its density.
In this case, salt increases the mass of the water, without increasing the volume of water. as the egg will not change in volume or water, we know that the density of the egg will be constant, while the change in the mass of the water with the addition of salt, will change the density of the water which will increase progressively until it becomes denser than the egg and, consequently, it will not let the egg sink.
Which of the following accurately represents the relationship between ceramic and
metal?
Relationship between metal and ceramic is accurately represented by the statement that metal is a better conductor than ceramics.
What are conductors?Conduction is defined as a process as a means of which heat is transferred from the hotter end of the body to it's cooler end.Heat flows spontaneously from a body which is hot to a body which is cold. Substances which enable conduction are called conductors.Conductors allow passage heat and electricity through the material.
In the process of conduction,heat flow is within the body and through itself.In solids the conduction of heat is due to the vibrations and collisions of molecules while in liquids and gases it is due to the random motion of the molecules .
When conduction takes place, heat is usually transferred from one molecule to another as they are in direct contact with each other.There are 2 types of conduction:1) steady state conduction 2) transient conduction.According to the type of energy conduction is of three types:
1) heat conduction
2) electrical conduction
3)sound conduction
Learn more about conductors,here:
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Why is it necessary to run TLC in a closed container and to have the interior vapor saturated with the solvent? What error is introduced into the determination of an Rf value if the top is left off of the developing chamber?
Answer:
See explanation
Explanation:
Rf value is known as retention factor.The retention factor of a particular material is the ratio of the distance the spot moved above the origin to the distance the solvent front moved above the origin(Harper College).
TLC is carried is out in a closed container and the interior is saturated with the solvent vapor in order to have a maximum resolution between components this prevents solvent from evaporating from the system.
Peradventure the solvent for the separation is partly or wholly lost due to an open container, the Rf value would be lower than the expected value.
Convection is said to occur in _______ , which includes liquids and gases.
A solvent was composed of two separate components: water and cyclohexane. If ethyl acetate was added to the solvent, into which layer would it most likely dissolve? Explain?
Answer:
water
Explanation:
In chemistry, an important principle that guides the solubility of a solute in a solvent is the principle of like dissolves like.
A polar solvent will dissolve a polar solute and a non-polar solvent will dissolve a non polar solute.
Ethyl acetate is a polar solute. It will have to dissolve in water which is a polar solvent. Hence, ethyl acetate will dissolve in the water layer.
a compound has a molar mass of 129 g/mol if its empirical formula is C2H5N then what is the molecular formula
Given :
A compound has a molar mass of 129 g/mol .
Empirical formula of compound is C₂H₅N .
To Find :
The molecular formula of the compound.
Solution :
Empirical mass of compound :
[tex]M_e = ( 2 \times 12 ) + ( 5 \times 1 ) + ( 1 \times 14 )\\\\M_e = 43\ gram/mol[/tex]
Now, n-factor is :
[tex]n = \dfrac{M}{M_e}\\\\n = \dfrac{129}{43}\\\\n = 3[/tex]
Multiplying each atom in the formula by 3 , we get :
Molecular Formula, C₆H₁₅N₃
The molecular formula of the compound is C₆H₁₅N₃.
Calculation:The Empirical mass of the compound is
[tex]= (2\times 12) + (5\times 1) + (1\times 14)\\\\[/tex]
= 43 gram/mol
Now n-factor should be
[tex]= 129 \div 43[/tex]
= 3
Now here we multiply every atom in the formula by 3 so it should be C₆H₁₅N₃
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